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Towards a fast, open-path laser hygrometer for airborne Eddy covariance measurements

Witt, Felix ; Nwaboh, Javis ; Bohlius, Henning ; Lampert, Astrid ; Ebert, Volker (2021)
Towards a fast, open-path laser hygrometer for airborne Eddy covariance measurements.
In: Applied Sciences, 11 (11)
doi: 10.3390/app11115189
Artikel, Bibliographie

Dies ist die neueste Version dieses Eintrags.

Kurzbeschreibung (Abstract)

Water vapor fluxes play a key role in the energy budget of the atmosphere, and better flux measurements are needed to improve our understanding of the formation of clouds and storms. Large-scale measurements of these fluxes are possible by employing the eddy correlation (EC) method from an aircraft. A hygrometer used for such measurements needs to deliver a temporal resolution of at least 10 Hz while reliably operating in the harsh conditions on the exterior of an aircraft. Here, we present a design concept for a calibration-free, first-principles, open-path dTDLAS hygrometer with a planar, circular and rotationally symmetric multipass cell with new, angled coupling optics. From our measurements, the uncertainty of the instrument is estimated to be below 4.5% (coverage factor k = 1). A static intercomparison between a dTDLAS prototype of the new optics setup and a traceable dew point mirror hygrometer was conducted and showed a systematic relative deviation of 2.6% with a maximal relative error of 2.2%. Combined with a precision of around 1 ppm H₂O at tropospheric conditions, the newly designed setup fulfills the static precision and accuracy requirements of the proposed airborne EC hygrometer.

Typ des Eintrags: Artikel
Erschienen: 2021
Autor(en): Witt, Felix ; Nwaboh, Javis ; Bohlius, Henning ; Lampert, Astrid ; Ebert, Volker
Art des Eintrags: Bibliographie
Titel: Towards a fast, open-path laser hygrometer for airborne Eddy covariance measurements
Sprache: Englisch
Publikationsjahr: 2021
Ort: Basel
Verlag: MDPI
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Applied Sciences
Jahrgang/Volume einer Zeitschrift: 11
(Heft-)Nummer: 11
Kollation: 10 Seiten
DOI: 10.3390/app11115189
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Kurzbeschreibung (Abstract):

Water vapor fluxes play a key role in the energy budget of the atmosphere, and better flux measurements are needed to improve our understanding of the formation of clouds and storms. Large-scale measurements of these fluxes are possible by employing the eddy correlation (EC) method from an aircraft. A hygrometer used for such measurements needs to deliver a temporal resolution of at least 10 Hz while reliably operating in the harsh conditions on the exterior of an aircraft. Here, we present a design concept for a calibration-free, first-principles, open-path dTDLAS hygrometer with a planar, circular and rotationally symmetric multipass cell with new, angled coupling optics. From our measurements, the uncertainty of the instrument is estimated to be below 4.5% (coverage factor k = 1). A static intercomparison between a dTDLAS prototype of the new optics setup and a traceable dew point mirror hygrometer was conducted and showed a systematic relative deviation of 2.6% with a maximal relative error of 2.2%. Combined with a precision of around 1 ppm H₂O at tropospheric conditions, the newly designed setup fulfills the static precision and accuracy requirements of the proposed airborne EC hygrometer.

Freie Schlagworte: water vapor, laser spectroscopy, near-infrared, dTDLAS, eddy covariance
Zusätzliche Informationen:

This article belongs to the Special Issue Diode Laser Spectroscopy – Robust Sensing for Environmental and Industrial Applications

Sachgruppe der Dewey Dezimalklassifikatin (DDC): 500 Naturwissenschaften und Mathematik > 530 Physik
600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau
Fachbereich(e)/-gebiet(e): 16 Fachbereich Maschinenbau
16 Fachbereich Maschinenbau > Fachgebiet Reaktive Strömungen und Messtechnik (RSM)
Hinterlegungsdatum: 16 Jan 2024 07:26
Letzte Änderung: 16 Jan 2024 07:26
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